The World Wide Web Consortium has announced the release of XML Inclusions (XInclude) Version 1.0 as a final W3C Recommendation. Produced by members of the W3C XML Core Working Group, XInclude "provides a generic method for merging XML documents into a single composite document. Using existing XML constructs (elements, attributes and URI references), XInclude contributes to efficient content management at the enterprise level."

The W3C announcement describes XInclude 1.0 as useful "in environments without DTD (Document Type Definition) support, which are more common since the adoption of XML schemas. Unlike the mechanism used in DTDs, i.e., XML external entities, XInclude gives the content author a fallback mechanism in cases where the external document cannot be retrieved, for whatever reason. XInclude allows an application to leverage the syntax in existing XML constructs... and allows an author to choose how to include another XML document in new composite content, either as markup or text. In addition, no XML entity declarations, which were required in the older method when using DTDs, are required for XInclude."

XInclude 1.0 takes advantage of the XML Information Set (Infoset), published as a Second Edition W3C Recommendation in February 2004. Because it merges XML information sets, XInclude "can be used with any version of XML, as well as other existing XML-related specifications, such as the XML-family components XML Schema and XSLT, as well as with XML applications such as the popular Scalable Vector Graphics (SVG) and VoiceXML 2.0 specifications. XInclude 1.0 also takes advantage of the XPointer Framework and can be used to include sub-resources, such as fragments of XML documents, that are identified by a separate xpointer attribute."

XInclude "differs from the linking features described in the W3C's XML Linking Language (XLink), which "specifically links with the attribute value show='embed'. Such links provide a media-type independent syntax for indicating that a resource is to be embedded graphically within the display of the document. XLink does not specify a specific processing model, but simply facilitates the detection of links and recognition of associated metadata by a higher level application. XInclude, on the other hand, specifies a media-type specific (XML-to-XML) transformation; it defines a specific processing model for merging information sets. XInclude processing occurs at a low level, often by a generic XInclude processor which makes the resulting information set available to higher level applications."

Paul Grosso of Arbortext praised XInclude for simplifying the creation and and management of "information components, making it easier for authors and organizations to reuse information in multiple documents and document types. Enabling more frequent reuse of information helps authors work more effectively while increasing the accuracy of information that they deliver. Arbortext enthusiastically contributed to the development of this Recommendation, and earlier this year we delivered support for XInclude in the Arbortext 5 release of our Enterprise Publishing software."

Ed Julson, Engineering Director of Web Technologies at Sun Microsystems said that the W3C XInclude Recommendation "provides a critical piece of infrastructure for compound document authoring not generally available in the post-DTD world. As evidence of our commitment to XInclude and open standards, Java 5.0 ships with support for XInclude today."

Henry Thompson, Reader in Artificial Intelligence and Cognitive Science at the University of Edinburgh, identified Xinclude as one of the W3C Recommendations used in the speech and language technology work at the School of Informatics: "XInclude addresses a key aspect of our work, namely the representation in XML of linguistic annotation which is not strictly hierarchical. XInclude will allow us to make our existing widely-used approach to this problem, know as Stand-off Markup, into full compliance with W3C Recommendations."

Bibliographic Information

• XML Inclusions (XInclude) Version 1.0. W3C Recommendation. 20-December-2004. Edited by Jonathan Marsh (Microsoft) and David Orchard (BEA Systems). Produced by members of the XML Core Working Group. Version URL: http://www.w3.org/TR/2004/REC-xinclude-20041220/. Latest version URL: http://www.w3.org/TR/xinclude/. Previous version URL: http://www.w3.org/TR/2004/PR-xinclude-20040930/.

• XML Information Set (Second Edition). Edited by John Cowan and Richard Tobin. W3C Recommendation. 4-February-2004. Version URL: http://www.w3.org/TR/2004/REC-xml-infoset-20040204. Latest version URL: http://www.w3.org/TR/xml-infoset. Previous version URL: http://www.w3.org/TR/2003/PER-xml-infoset-20031210.

From the W3C Announcement

Strengthening the XML family, the World Wide Web Consortium (W3C) has published XML Inclusions (XInclude) Version 1.0 as a W3C Recommendation. XInclude 1.0 provides a method for merging multiple XML documents into a single composite document.

Many programming languages provide an inclusion mechanism to support the use of modular content. Once an inclusion mechanism is established, programmers can then write applications that are more powerful. Markup languages, of course, often have need of such a mechanism.

XInclude 1.0 is a generic mechanism for merging XML documents. This function is important for software applications that need to easily combine XML documents.

"For most users, XInclude makes it easier to author content that supports information reuse. Reusing information contributes directly to the bottom line issues: cheaper, more timely, and more accurate results," says Paul Grosso, co-Chair of the XML Core Working Group which produced XInclude.

The W3C was created to lead the Web to its full potential by developing common protocols that promote its evolution and ensure its interoperability. It is an international industry consortium jointly run by the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL) in the USA, the European Research Consortium for Informatics and Mathematics (ERCIM) headquartered in France and Keio University in Japan. Services provided by the Consortium include: a repository of information about the World Wide Web for developers and users, and various prototype and sample applications to demonstrate use of new technology. More than 350 organizations are Members of W3C... [see the complete text]